JIRA: Custom fields for initiatives -> JIRA custom fields Merged

Initiatives can now have custom fields, the values however are not available to configure through the JIRA integration mapping.

This prevents sending the custom field values for initiatives in Aha! to JIRA.

This is particularly important when the JIRA environment has required fields that need to be defined in Aha! to create the epic in JIRA when initiatives = epics.